Variation in mitochondrial DNA reveals multiple distant glacial refugia in black spruce (<i>Picea mariana</i>), a transcontinental North American conifer
Bibliographic record
Abstract
Range-wide genetic variation of black spruce (Picea mariana) was studied using polymerase chain reaction-random fragment length polymorphism markers of the mitochondrial genome. Four polymorphic mitochondrial DNA (mtDNA) loci were surveyed and two or three alleles were detected at each locus, resulting in 10 multilocus mtDNA types or mitotypes. A significant subdivision of population genetic diversity was detected (GST = 0.671; NST = 0.726), suggesting low levels of gene flow among populations. The distribution of mitotypes was not random (NST > GST; P < 0.05) and revealed four partially overlapping zones, presumably representative of different glacial populations. Comparison of the genetic structure derived from mtDNA markers and the colonization paths previously deduced from the fossil and pollen records allow us to infer at least three southern and one northeastern glacial populations for black spruce. The patterns revealed in this study suggest that black spruce shares its biogeographical history with other forest-associated North American species.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".